This invention relates to a composite tool unit of the type known from European Patent No. A1-0010074.
In modern machine tools, in which the tool unit according to the invention is used, the tool cutting edges are subjected to very heavy stressing. This demands frequent changing of the cutting edge. Furthermore, to make such machine tools usable for all purposes, one tool must often be very quickly replaced by a differently designed one. It is therefore known to produce the tool in composite form, comprising a tool shank which is left on the machine, and a tool head which can be unturnably connected to the tool shank via a coupling, the tool head bearing the cutting edge.
The known tool unit of the kind specified has prismatic guide faces at the separating place between the tool shank and the tool head. The drawbar has a cylindrical pulling head which engages in a recess in the tool head which is open on a narrow side. The recess has a keyhole-like cross-section. In the case of that tool unit the tool head can only be connected to the tool shank when the latter is in a pre-determined turned position. The tool head and tool shank are connected and separated over a path of movement extending substantially at right angles to the longitudinal axis of the tool shank.
The invention relates to the problem of providing a composite tool unit of the kind specified whose tool head can be very simply and rapidly connected to the tool shank and again released therefrom and which in the connected position is highly nondeformable and stable, even in the face of cutting forces which change during the machining operation.